A note on dates: the naval engagement at the center of this entry took place on July 16, 1863. This chronicle entry is assigned July 23 and covers the wider Shimonoseki crisis of that summer — the tense, violent weeks when samurai domain politics collided with the physical reality of modern naval power in one of the most strategically vital passages in all of Japan.

The 下関海峡 (Shimonoseki Kaikyō — Shimonoseki Strait) is barely half a mile wide at its narrowest. Every ship moving between the 瀬戸内海 (Seto Naikai — Inland Sea) and the Korea Strait had to pass through it. In the spring of 1863, that waterway became a flashpoint for the collision between two visions of Japan's future.

The imperial court, pressured by anti-foreign daimyo and emboldened by the 尊王攘夷 (sonnō jōi — revere the emperor, expel the barbarians) movement, issued a decree on May 10, 1863 ordering foreign ships expelled from Japanese waters. Most of the shogunate's allies quietly ignored it. The 長州藩 (Chōshū Han — Chōshū domain), led by lord 毛利敬親 (Mōri Takachika), did not. They had the guns and the strait. They used both.

On May 26, Chōshū shore batteries opened fire on the American merchant vessel Pembroke as it transited the strait. Over the following weeks they fired on a French dispatch vessel and a Dutch warship. The samurai of Chōshū genuinely believed they were executing a sacred imperial command — that the foreign ships would turn back, that the spirit of Japan could close the sea lanes that geography had made indispensable.

Captain David McDougal of the USS Wyoming heard the reports and made his own calculation. On July 16, 1863, he sailed his single warship into the Shimonoseki Strait alone. He had no squadron. He had no orders from Washington to engage. He had a ship and a judgment that attacks on American vessels required an answer.

What followed was nearly two hours of close-range fighting in one of the narrowest contested waters imaginable. The Chōshū fleet — a steam bark, a brig, and a screw steamer, plus shore batteries firing from the bank — was outmatched in every technical dimension. Wyoming sank two vessels outright, severely damaged a third, and inflicted approximately forty Japanese casualties before withdrawing. She was badly damaged herself and lost four crew dead, seven wounded. At one point she grounded briefly on uncharted shallows, sitting stationary under enemy fire, before breaking free to continue the fight.

One detail from the Chōshū fleet is worth noting: among their vessels was an American-built steam bark. Chōshū samurai had purchased or acquired Western machinery they did not yet fully know how to operate — and were firing it, imperfectly, at the nation that had built it. The irony was almost too sharp to be real.

The Chōshū batteries survived the Wyoming's engagement intact. The strait was not cleared. But the battle demonstrated in the plainest possible terms that Chōshū's naval strength was no match for a modern Western warship — even one acting alone, without support, against a fortified position. The following month, a French naval squadron bombarded Chōshū shore installations. In 1864, a four-nation allied fleet comprising American, British, French, and Dutch warships arrived and destroyed the Shimonoseki fortifications in a single coordinated campaign.

The aftermath was not what the 攘夷 (jōi) ideologues had expected. Chōshū, the domain that had screamed loudest for the expulsion of foreigners, emerged from its military humiliation convinced of exactly the opposite lesson: Japan had to modernize its military or be destroyed by those who already had. The same samurai who had loaded those shore guns became some of the most aggressive advocates for Western-style military reform. Within a decade, Chōshū warriors in Western uniforms were helping dismantle the shogunate entirely and build the Meiji state in its place.

A word that had seemed like a battle cry — 攘夷 (jōi): expel the barbarians — turned out to be the first step toward the opposite conclusion. The strait that Chōshū tried to close became, in the end, the place where Japan's old certainties broke apart.